/*
 * Copyright 2002-2016 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.http;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.charset.Charset;

import static org.mockito.Mockito.spy;

/**
 * @author Arjen Poutsma
 * @author Rossen Stoyanchev
 */
public class MockHttpOutputMessage implements HttpOutputMessage {

    private final HttpHeaders headers = new HttpHeaders();

    private final ByteArrayOutputStream body = spy(new ByteArrayOutputStream());
    private final HttpHeaders writtenHeaders = new HttpHeaders();
    private boolean headersWritten = false;

    @Override
    public HttpHeaders getHeaders() {
        return (this.headersWritten ? HttpHeaders.readOnlyHttpHeaders(this.headers) : this.headers);
    }

    /**
     * Return a copy of the actual headers written at the time of the call to
     * getResponseBody, i.e. ignoring any further changes that may have been made to
     * the underlying headers, e.g. via a previously obtained instance.
     */
    public HttpHeaders getWrittenHeaders() {
        return writtenHeaders;
    }

    @Override
    public OutputStream getBody() throws IOException {
        writeHeaders();
        return body;
    }

    public byte[] getBodyAsBytes() {
        writeHeaders();
        return body.toByteArray();
    }

    public String getBodyAsString(Charset charset) {
        byte[] bytes = getBodyAsBytes();
        return new String(bytes, charset);
    }

    private void writeHeaders() {
        if (this.headersWritten) {
            return;
        }
        this.headersWritten = true;
        this.writtenHeaders.putAll(this.headers);
    }

}
